In July 2017 the UK Supreme Court clarified the circumstances in which the monopoly granted by a patent could be widened beyond the normal interpretation of the claim to cover variants which have no material effect on the way the invention works.

This judgment is regarded as introducing a ‘doctrine of equivalents’ into English patent law, which has the effect of broadening the claim for infringement purposes beyond its normal meaning to include immaterial variants (or equivalents). See our article on the Supreme Court case ­– Actavis UK Ltd and others v Eli Lilly and Company - here.

As is often the case when a decision makes a significant change to the law, further questions as to the implications of the change are now arising. Two recent High Court decisions have considered questions of interpretation and novelty as set out below.

Does the English courts’ traditional ‘purposive’ approach to claim construction still apply?

The doctrine of equivalents broadens the claim for infringement purposes beyond its normal meaning to include equivalents. But what is the ‘normal meaning’ of the claim for this purpose? Is it the literal meaning of the words or should the claim be construed ‘purposively’ in accordance with previous English case law? The High Court has now held that a purposive approach should be taken. Such a purposive construction takes into account what the person skilled in the art would have understood the claim to mean bearing in mind that the patentee’s purpose was to describe and claim an invention and bearing in mind its context. This purposive construction may (but will not necessarily) allow a broader interpretation of the claim that includes trivial or minor variants where the person skilled in the art would assume that the patentee had meant to include these. So far two High Court decisions have taken the view that this purposive construction of the claim still applies.

How does the doctrine of equivalents affect novelty?

The two High Court cases in question also both considered whether a variant (or equivalent) in a prior publication would destroy the novelty of the patent. Prior to the Supreme Court’s decision there was a general principle in English patent law that if a prior publication disclosed subject-matter which, if performed, would necessarily result in infringement then the claim would lack novelty. This implied that the claim must be construed in the same way for validity and infringement purposes. However, the High Court has now questioned this principle based on the Supreme Court decision, holding that the claim would only lack novelty if the prior art disclosure would infringe the claim on its proper interpretation, without taking equivalents into account. The new position therefore seems to be that equivalents in a prior art publication are to be disregarded in relation to novelty. It should be noted, however, that equivalents may be taken into account in relation to obviousness, so that the patent could fail at the obviousness hurdle.

As these question go to the crucial issue of how broad the patent monopoly should be it is unlikely that we have heard the last of it, and we can expect these arguments to be raised before the higher courts in the not too distant future.

The first case, Generics v Yeda (26 October 2017), related to a patent for a dosage regime for the blockbuster drug Copaxone, a treatment for multiple sclerosis marketed by Teva under licence from Yeda. The second case, Fisher & Paykel Healthcare v Resmed (10 November 2017), related to a patent for a face mask used in the treatment of obstructive sleep apnoea.